In general, a fuel cell is an electrochemical device that can convent energy stored in fuels such as hydrogen, methane, methanol and the like, into electricity without combustion of the fuel. A fuel cell generally comprises a negative electrode, a positive electrode, and a separator within an appropriate container. Fuel cells operate by utilizing chemical reactions that occur at each electrode. In general, electrons are generated at one electrode and flow through an external circuit to the other electrode where they are consumed. This flow of electrons creates an over-voltage between the two electrodes that can be used to drive useful work in the external circuit. In commercial embodiments, several “fuel cells” are usually arranged in series, or stacked, in order to create larger over-potentials.
A fuel cell is similar to a battery in that both generally have a positive electrode, a negative electrode and electrolytes. However, a fuel cell is different from a battery in the sense that the fuel in a fuel cell can be replaced without disassembling the cell to keep the cell operating. Additionally, fuel cells can have several advantages over other sources of power that make them attractive alternatives to traditional energy sources. Specifically, fuel cells are environmentally friendly, efficient and utilize convenient fuel sources, for example, hydrogen or methanol.
Fuel cells have potential uses in a number of commercial applications and industries. For example, fuel cells are being developed that can provide sufficient power to meet the energy demands of a single family home. In addition, prototype cars have been developed that run off of energy derived from fuel cells. Furthermore, fuel cells can be used to power portable electronic devices such as computers, phones, video projection equipment and the like. Fuel cells designed for use with portable electronic equipment provide an alternative to battery power with the ability to replace the fuel without replacing the whole cell. Additionally, fuel cells can have longer power cycles and no down time for recharging, which also makes fuel cells an attractive alternative to battery power for portable electronics.
As described above, fuel cells are becoming an increasingly attractive alternative to traditional energy sources such as batteries and fuel combustion. For example, fuel cells are currently being developed to power portable electronic devices such as, for example, laptop computers, video projection equipment and the like. It may be convenient for fuel cells designed for use with portable electronic devices to be compatible with portable and interchangeable fuel containers, which permit empty or partially empty fuel containers to be replaced in order to keep the fuel cell, and ultimately the portable electronic device, operating. In some embodiments, these fuel cells are designed to use liquid fuels such as, for example, methanol, although they can use other fluid fuels, such as compressed hydrogen or methane.
Generally, fuel containers or fuel cartridges suitable for use with portable electronic devices comprise a storage structure having a suitable fuel located therein. Additionally, these fuel containers can further comprise a passage which provides access to the interior of the container or cartridge. In some embodiments, the pass is coupled to a connector that is adapted to couple with a fuel inlet port on a portable fuel cell to establish fluid communication between the fuel cell and the fuel container once appropriate valves or other control element are opened. In one embodiment, fuel containers suitable for use with fuel cells designed for portable electronic devices can comprise a rigid outer container associated with a flexible inner container in which a fluid such as, for example, methanol is stored. In some embodiments, these types of fuel containers can further comprise a port in the outer container which allows transport of the filled inner container into the outer container. These types of fuel containers are described in, for example, commonly assigned and co-pending U.S. patent application Ser. No. 10/384,382, filed on Mar. 7, 2003, entitled “Fuel Storage Container For A Fuel Cell,” which is hereby incorporated by reference herein. In addition, methanol, and other organic fluids suitable for use in fuel cell applications, are generally environmental pollutants and flammable and, therefore, can present safety and other release issues. As a result, it may be desirable to reduce the amount of potential fluid leakage during engagement of the fuel container with the fuel cell, while still maintaining the ability to quickly connect and disconnect the containers from the fuel cell.